Evacuation of condensate



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Patented July 25, 1933 UNITED STATES PATENT OFFICE HERVEY G. CRAM, 0F BUOKSPORT, MAINE, ASSIGNOR TO MAINE SEABOARD PAPER COMPANY, OF BUCKSPORT, MAINE, A CORPORATION OF 'MAINE EVAGUATION OF CON DEN SATE Application filed September 25, 1931.

' a construction which will efiect substantially complete evacuation of the water of condensation.

My invention will be well understood from the following description, wherein for convenience I will describe the device specifically as applied to a paper-drying roll, taken in connection with the accompanying drawing, wherein Fig. l is a longitudinal section of the roll with part broken away;

Fig. 2 is a section on the line 22 1 on an enlarged scale;

Fig. 3 is a bottom plan view of the end of the eduction pipe as seen from line 33 of Fig. 1; and

Fig. i is a fragmentary enlarged view of the end of the pipe as seen in Fig. 1.

Referring to the drawing, I have shown in Fig. 1 a drier roll 5 adapted to turn on the bearings 7 and having extending into one of these bearings a pipe ,9 for admitting steam to the interior of the roll. An eduction pipe 11 extends through the bearing and may extend curvilinearly in a substantially radial plane to present its end in close opposition to the exterior wall of the cylinder near the bot tom. The usual means, not herein shown, may be provided for adjusting the spacing of the end of the pipe from the interior wall of the roll and for varying the angular position of the pipe. By the latter reference I refer to the fact that while the pipe extends to the bottom of the cylinder, its end need not be presented in the sixoclock position, but may be displaced to compensate for the displacement due to its inertia when the cylinder is rotated of the water accumulated therein. These eduction pipes in paper mill practice are commonly referred to as siphons, although in present-day practice a substantial differential steam pressure is maintained such that the discharge through the pipe is substantially continuous. In other words, theoretically the steam pressure is such that water is discharged up the pipe at all times unless of Fig.

Serial N 0. 565,032.

and until the level falls below the open end of the pipe.

Hithereto, however, in paper mill practice a body, of Water has remained in the roll equivalent to, say, three inches in depth, although, of course, theend of thepipe has been adjusted closer than three inches to the surface of the roll. Conditions in the interior of the roll are not susceptible to inspection during operation, and while various theories may be advanced I content myself with stating the conditions as theyhave obtained in practice.

The body of water which thus remains in the roll presents a resistance to the turning of the same, the effect of which is particularly felt as the paper making machinery is operated at increased speeds, and the consumption of power necessary to operate the drying roll system has been excessive. By the construction which I am about to describe substantially complete evacuation in the water is effected and the power demand re duced.

Referring now to Figs. 2, 3 and 4, I have there shown the wall of the pipe 11 cut away laterally at one side to provide a recess at 13 of small height and facing, as indicated by the arrow in Fig. 4, in a direction opposite to that in which the cylinder rotates and opposed on the further side of the pipe by the interior face 15 of the Wall of the pipe. The port defined by this recess ispreferably of reduced area as compared with the cross section of the pipe 11 for reasons which will appear. By way of example and without limitation thereto, I may say that I have had good results with a pipe of about 1 interior diameter'in which the recess was A high and about 1 Wide. Preferably means are provided for defining a tapered passage to the port 13 referred to and I have herein shown an overhanging bevelled flange 17 at the top of the recess and flaring flanges 19 at either side thereof. The open end of the pipe is presented in close opposition to the interior wall of the cylinder and it may conveniently be adjusted into actual contact with the wall so that when the roll is revolved the end of the pipe will gradually grind itself into a fit, leaving open the lateral port at 13.

The particular construction illustrated and just described as an illustrative embodiment of the invention in practice will effect a substantially complete evacuation of the water. If port 13 is submerged, the steam pressure is effective to force water out as in the devices of the prior art. My construction presents an advantage, however, in "that the end of the pipe may be adjusted into contact with the bottom of the cylinder without shutting off the discharge and a close adjustment thus provided certainly and without difliculty. Then the port 13 is in part uncovered, evacuation of the water apparently continues and, without limiting myself thereto, I advance the following explanation of the action. In the rotation of the cylinder in the direction of the arrow in Fig. 2 water carried along due to the rotation of the cylinder enters at 13 and will surge against the wall 15 presented substantially directly transversely to the course of its motion and will rebound therefrom, creating a turbulence at the end of the pipe. At the same time steam will escape through the port at 13, which may be more or less closed at the bottom part by the water,

and in passing through this restricted aperture its velocity is greatly increased. The wateriis therefore picked up and carried up the pipe by impulse assisted by the flow of steam inthe same direction. There may also be some condensation of steam as it passes into contact with the water without loss of velocity, and the steam thus condensed carries with it further water by injector ac tion.

I may also provide a cross current longitudinally of the c linder to provide a turbulence adjacent t e pipe and at the mouth of port 13. Herein I have shown the interior surface of the cylinder as provided with a thread 21" which serves to feed the water lengthwise thereof and toward that end at which the eduction pipe is placed. As drier cylinders are bored in'the course of manufacture, such a thread, which need be very slight, may be conveniently cut by the use of a suitable tool during the boring of the cylinder. I have found a pitch of perhaps 8" as effective in a paper drying cylinder of a diameter of 5' and an interior length of about 19. Water-feeding means of this type will also assist the normal levelling process of the water and resist'the tendency of the 7 water to accumulate at one end of the cylinder to relatively great depth.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive; reference being had to the appended claims rather than to the foregoing description to indicate the scope of the invention.

I claim:

1. In combination with a rotating steamheated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe having an end closely opposed to the cylinder wall adjacent the bottom thereof and a lateral steam .port of reduced area relative to the section of said pipe located adjacent said end.

2. In combination with a rotating steamheated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe having an end closely opposed to the cylinder wall adjacent the bottom thereof and cut away at one side to provide a shallow recess.

3. In combination with a rotating steam heated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe having an end closely opposed to the cylinder wall adjacent the bottom thereof and cut away at one side to provide a shallow recess and having flanges defining a passage converging toward said recess.

4. In combination with a rotating steamheated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe having its end close: 1y opposed to the cylinder wall adjacent the bottom thereof and having a water inlet and a tapered steam passage providing a throat of restricted capacity through which steam may pass from the interior of the cylinder ice the pipe into contact with water at said in- 5. In combination with a rotating steamheated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe having its endspresented in a substantially radial plane in close opposition to the cylinder wall adjacent the bottom thereof and having its wall formed with a shallow recess facing in a direction opposing the motion of the cylinder.

6. In combination with a rotating steamheated cylinder, means for evacuating condensate therefrom comprising a relatively stationary eduction pipe extending into close opposition to the wall of the cylinder adjacent the bottom thereof, the end of the pipe presenting an exposed substantially radial interior wall opposed to the direction of motion of the cylinder and having a reduced port providing for discharge of steam at greatly increased velocity into contact with water surging against said wall, the interior surface of the cylinder being provided with means to feed water longitudinally of the cylinder toward and across the end of the pipe.

HERVEY G. CRAM. 

